Related Experiment Video
Updated: May 23, 2026
05:04
Determining the Mechanical Strength of Ultra-Fine-Grained Metals
Published on: November 22, 2021
Structurally Complex Precipitates Enhance Strength-Ductility Synergy in a Duplex Medium Entropy Alloy
Shaohua Gao1, Yang Yang1, Xiaoxuan Fan1
1State Key Laboratory For Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, P. R. China.
Summary
Researchers designed complex intermetallic nanoprecipitates (INPs) with core-shell structures in medium-entropy alloys. This approach enhances both strength and ductility, overcoming limitations for cryogenic applications.
Area of Science:
- Materials Science
- Metallurgy
- Nanotechnology
Background:
- Intermetallic nanoprecipitates (INPs) offer high strength but suffer from brittleness and glide-plane softening, limiting uniform elongation.
- This strength-ductility trade-off is worsened at cryogenic temperatures due to the brittleness of bcc phases in fcc/bcc alloys.
Purpose of the Study:
- To design structurally complex, ductile B2 multicomponent INPs (MINPs) with core-shell nanostructures.
- To overcome the limitations of conventional INPs in precipitate-strengthened alloys for cryogenic applications.
Main Methods:
- Fabrication of duplex fcc/bcc Fe58Ni16Cr16Al10 (at%) medium-entropy alloys (Fe-MEAs).
- Characterization of coherent core-shell B2 MINPs with dispersive nanocores and chemical-heterogeneity shells.
- Analysis of dislocation behavior and mechanical properties under cryogenic conditions.
Main Results:
- The designed core-shell B2 MINPs act as effective dislocation sources and obstacles, enhancing load transfer and self-hardening.
- Suppression of glide-plane softening and activation of unusual ⟨111⟩ dislocation multiplication under cryogenic conditions.
- Achieved high yield strength and large uniform elongation in Fe-MEAs.
Conclusions:
- Structural complexification of MINPs is a viable strategy for designing self-hardening materials.
- The developed core-shell nanostructure enables ductile, high-strength materials for advanced cryogenic structural applications.
Related Concept Videos
01:24Stress-Strain Diagram - Ductile Materials
The stress-strain relationship in ductile materials such as structural steel or aluminium is intricate and progresses through several stages. When a specimen is loaded, it initially exhibits a linear length increase, depicted by a steep straight line on the stress-strain diagram. It indicates the material is elastically deforming and will return to its original shape once unloaded. However, when a critical stress value is reached, plastic deformation begins. This stage sees substantial...
01:19Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
01:25Yield Criteria for Ductile Materials under Plane Stress
In designing structural elements and machine parts using ductile materials, it is crucial to ensure that these components withstand applied stresses without yielding. Yielding is initially determined through a tensile test, which evaluates the material's response to uniaxial stress. However, tensile stress is insufficient when components face biaxial or plane stress conditions This condition requires advanced criteria to predict failure.
The Maximum Shearing Stress Criterion, also known as the...
The Maximum Shearing Stress Criterion, also known as the...
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
01:26Hooke's Law
Hooke's law, a pivotal principle in material science, establishes that the strain a material undergoes is directly proportional to the applied stress, defined by a factor called the modulus of elasticity or Young's modulus.
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...